OK, this came up in conversation recently and sounded like an intresting exercize. Is it possible to fake infrared B&W using Photoshop?

Here's my theory: it might be possible if one were to start with a color image, then adjust the color balance sliders to reflect infrared film's sensitivity levels to different colors in the spectrum. The final step would be to reduce the hue down to -100% and perhaps run it through a film grain filter to add that grainy effect.

Has anyone tried this? Does it sound feasable, or am I getting wacky in my old age?

Cheers, Mason

-- Mason Resnick (bwworld@mindspring.com), May 16, 2000

Answers

Depends on the subject matter. Landscapes should be easy, you take the green layer, lighten it, add a halo filter effect + add noise, recombine the layers, desaturate and viola! (as the small cello player said).

Portraits won't be so easy. You need to exaggerate the veins and skin blemishes for a start. Wind up the blue saturation? Anyway half the fun is in the playing. Go to it!

-- Pete Andrews (p.l.andrews@bham.ac.uk), May 16, 2000.

It is probably feasible for some applications, but why? Half the fun of using IR film is USING IR film... having to load your camera in the dark, having no clue what the correct exposure should be, bracketing like heck and waiting anxiously to see how the negatives turned out. I think it would be very difficult to exactly match the tonality and renditions of IR film, but I think I'll just stick to buying the film and crossing my fingers. :)

-- Jim MacKenzie (photojim@yahoo.com), May 16, 2000.

I guess it's like many of these fakes: You may fake something and even achieve a convincing look, but it's not the real thing. Why bother to justify abstractions? If you visualise an image in a special way and use digital manipulations to make a conventional photo look like what you visualised, that's OK in its own right. You may mention that you got the idea from b&w IR, but it's still a result of your creativity.

As for the principle: You can't reliably fake an image recorded using invisible electromagnetic radiation on the basis of an image taken using visible radiation only. That's why the blood vessels and stubbles in actual IR portaits, and all the other things invisible to the naked eye (and to conventional film) are hard to fake.

-- Thomas Wollstein (thomas_wollstein@web.de), May 18, 2000.

There's a guy over at www.photocritique.net that has done a few of these. The effect had a infrared look but not the same and not much detail in the lighter areas... not sure why. I maybe be off the mark, but I think he takes the red channel and does something with it! Just checked his pictures and he's removed them.

-- Nigel Smith (nlandgl@eisa.net.au), May 18, 2000.

there was an article regarding this in 'outdoor photographer' last fall, maybe sept. or oct.. loosely, i remember using the red channel, selecting color range (using additive eyedropper), expanding and feather the selection, and filling it with a low percentage of white. as stated earlier, this works well for landscapes, but to mimmick the effect for portraits would be diffucult...hope that maybe helps.

-- jerry hazard (hazard01@earthlink.net), June 16, 2000.

You really can't fake IR results this way except in the way that you could paint a picture. IR film's sensitivity is beyond what panchromatic emulsions have, not a reduction of it.

As an analogy, you could easily make an orthochromatic look from a panchromatic shot because ortho is the same as panchro without the red sensitivity. But you can't make an ortho shot look like panchro because it didn't record the reds in the first place.

Another way to look at it is that live healthy foliage reflects IR. It itsn't that IR sees green as a light shade, but that it sees the IR. Unhealthy foliage doesn't reflect IR, so it looks darker.

Water, which we frequently see as blue, shows as black in IR. It isn't that IR film sees blue as dark (in fact IR is fairly sensitive to blue light) but that water absorbs IR to a great extent, so it looks dark to the film.

IR light is a different color that the ones we see, not a variation or blending of ROYGBIV. A color photo doesn't have IR as one of the colors it records, so it isn't in the slide/print/scan for your program to alter. Color IR film isn't the same as B&W. They take one of the 3 colors and sensitize it to IR, so the color balance is shifted. But the end result is not the same as B&W IR.

In any case, I agree with the previous post. If you like IR and its look the easiest thing to do is just use it in the first place.

-- Charlie Strack (charlie_strack@sti.com), July 14, 2000.